The present disclosure relates to biopsy devices and particularly to core biopsy devices.
A standard single action biopsy device has an outer cannula needle coaxially disposed over an inner stylet needle. The inner stylet defines a specimen notch near the distal end. The outer cannula and inner stylet are each attached to hubs and the hubs are moveable between three positions via a spring activated mechanism. The first position is a fired or neutral position. The proximal ends of the needles, the spring and carriages are housed within a casing including a handle. A plunger is engaged to the carriages. In use, the plunger is pulled back to charge the device. In the charged condition, the carriages and needles have been pulled back into the casing. When the device is charged the plunger is moveable between back and forward positions. In the forward position, the stylet has been moved forward relative to the outer cannula to expose the notch. Depressing the plunger further fires the device by releasing the outer needle carriage so that the outer needle quickly moves forward to cover the notch and sever tissue to capture a specimen within the notch.
In a single action Device, the inner stylet with the notch is manually moved with the plunger. In a double action device, both the inner stylet and outer cannula are fired automatically in rapid succession once the trigger is depressed. One advantage of a single action device over a double action device is that manual movement of the inner stylet allows the clinician to directly visualize how far the outer cannula will core tissue by noting the location of the distal point of the inner stylet. This allows the clinician to avoid coring vital structures. Some clinicians also can feel the difference between target or safe tissue and vital structures by manually moving the inner stylet with the plunger. The resistance of such tissue against movement of the stylet tip provides different tactile feedback. Using a double action device, on the other hand requires the clinician to measure the length of the throw to estimate whether the device will core a vital structure.
Both single action and double action devices reliably deliver core specimens, but they are limited in regard to the amount of tissue specimen by the dimensions of the notch. The BioPince™ device of Argon Medical Devices, Inc., was a major advancement in the field of biopsy because it provided a full rounded core, which was much larger than the specimens delivered by the “side notch” in the stylet of the single action and double action devices. While a major contribution, the BioPince had a relatively large casing and complicated mechanism.
The DEX360 Full Core Biopsy device of Promex Technologies, Inc., utilized forcing cone technology to deliver a large rounded full core with a simple, elegant mechanism. While the full core performance of both the BioPince and the DEX360 devices deliver clinically significant better cores, both devices operate like double action devices in that the clinician must measure the throw before firing.
The current invention combines the benefit of manual advancement of the inner member before coring of a single action with the forcing cone feature of a DEX360. When the plunger is advanced, a scoop portion defined in the inner needle is extended for tissue prolapse. The forcing cone in the outer cannula in combination with the scoop captures a rounded core. In some embodiments, the distal end of the scoop includes a sharpened tip, a partial forcing cone or a solid tip. For the present disclosure certain aspect of these improvements are described for use with a full-core biopsy device, such as the device described in U.S. Pat. No. 9,332,970, which was filed on Sep. 13, 2012 and issued on May 10, 2016, pending application Ser. No. 13/190,808, filed on Jul. 26, 2011, and U.S. Pat. No. 9,237,883 which was filed on Dec. 16, 2010, and issued on Jan. 19, 2016, all of which are entitled “Full Core Biopsy Device”. The descriptions of the full core biopsy devices in these applications are incorporated herein by reference, but for the purposes of the present application certain features of the disclosed devices will be described herein.
One type of core biopsy device 10 is shown in FIG. 1. The device 10 includes a housing 12 that defines finger handles 14 to be grasped by the clinician during a biopsy procedure. The device can include an outer cannula or cannula 20 and an inner member 30, which may be a stylet, needle or cannula, coaxially extending through the outer cannula 20. The biopsy device 10 incorporates a mechanism for charging and firing the outer cannula relative to the inner member in order to capture a tissue sample. One embodiment of a firing mechanism is incorporated into the SABD™ product and is described in the above-referenced pending applications. In general terms, the mechanism includes carriages that carry the outer cannula and inner member, and a spring arrangement that extends the outer cannula beyond the inner member so that tissue is drawn into and trapped in the tip 26 of the outer cannula. It is noted that this outer-inner cannula relationship is not utilized in the SABD, the inner cannula is extended so tissue can prolapse into the cannula before the outer cannula fires over the inner. In is noted that the scoop cannula of the present disclosure operates in the same manner to accept tissue prolapsed into the scoop portion.
The mechanism of the full core device includes latch arrangements that allow the biopsy device to be placed in a charged configuration in which the tip 26 of the outer cannula is retracted, and then allow the device to be fired. A plunger 32 may be used to manually charge and fire the biopsy device. It should be appreciated, however, that the components described herein may be used in other types of biopsy devices, such as fully automated or double action devices.
According to one aspect, the tip 26 of the outer cannula 20 is provided with a tissue penetrating tip. In one specific aspect the tissue penetrating tip is formed as a Franseen tip, as shown in FIG. 2, having three or more prongs 27 with sharp cutting edges that permit smooth piercing of the soft tissue as the outer cannula 20 initially advances into the tissue and that provide solid purchase once the outer cannula has been fully advanced. The prongs 27 are configured to advance through the tissue without substantially compressing the tissue. The angled edge surfaces of the prongs 27 act as guillotine cutters to slice cleanly through the tissue as the outer cannula 20 advances. The distal portion of the outer cannula forms a tissue specimen chamber.
In another aspect, the distal portion of the tissue specimen chamber defines a tissue retention feature in the form of a countersink or forcing cone 28 defined in the inner surface to a depth 29 that is proximal from the valleys of the Franseen tip 26. The forcing cone has a larger inner diameter than the proximal portion of the tissue specimen chamber. The forcing cone 28 essentially “forces” or squeezes a larger diameter of tissue into the relatively smaller diameter of the tissue specimen chamber of the outer cannula beyond the forcing cone as it is advanced into the tissue, which allows for a larger diameter sample and holds the sample in place as the device is withdrawn from the biopsy site. Employing a forcing cone for the tissue retention feature allows for the entire inner diameter of the outer cannula to be available as the tissue specimen chamber. It is believed that the force of the tissue against the sidewall of the outer cannula is greater than the force folding the cells together at the end of the specimen. Therefore when the needle is withdrawn, the tissue separates at a natural plane making any other tissue separation or retention means redundant. The forcing cone 28 may be incorporated into the outer cannula of different types of biopsy devices, including side notch devices, single or double action devices and coring devices.
In the charged configuration or position of the biopsy device, the inner member 30 is situated within the outer cannula 20 so that the tip 36 preferably does not extend beyond, or extends only minimally beyond, the base of the valleys of the Franseen tip 26, as illustrated in FIG. 3. It can be appreciated that in the charged position shown in FIG. 3, the inner member hub 32 is in position to fire the device 10.